Aircraft frequently fly in formation. Each aircraft in a formation flight occupies and maintains a position relative to each other aircraft in the formation. Such a relative position is referred to as a station, and maintaining that relative position is referred to as station keeping.
Formations may be flown by a variety of aircraft for a number of reasons. For example, civil aircraft may be flown in formation as part of flying club activities. As a further example, civil and military aerobatics teams, such as the U.S. Navy Flight Demonstration Squadron (well known the world over as “The Blue Angels”) perform aerobatics maneuvers in formation. In the example of The Blue Angels, high-performance tactical aircraft, such as the F/A-18 Hornet manufactured by The Boeing Company, are flown at speeds in excess of 500 knots in formations with as little as eighteen inches of separation between a wingtip of one plane and the helmet of the pilot of an adjacent plane in the formation.
In the above examples, station keeping is performed visually. As a result, formation flights and aerobatic shows are limited to visual flight rules (VFR) conditions.
Advances in avionics have resulted in development of avionics systems that autonomously perform station keeping for formation flights that entail larger separations than the miniscule separation precisely maintained by The U.S. Navy Blue Angels. For example, the C-17 Globemaster III transport, manufactured by The Boeing Company and flown by the U.S. Air Force, currently employs an avionics system to allow C-17 Globemaster III aircraft to fly autonomously in formation.
In response to operational commitments, it may be desirable to fly aircraft, such as the C-17 Globemaster III transport, in formation in other-than-VFR conditions, such as Instrument Flight Rules (IFR) conditions due to low visibility or other weather-related conditions. Currently known systems adequately perform autonomous station keeping functions for formation flights of C-17 Globemaster III transports in VFR conditions. However, operational experience has indicated that improvements are desirable for autonomous station-keeping in low visibility conditions.
Therefore, there is an unmet need in the art for a system that autonomously performs station keeping functions for formation flights—even in low visibility conditions.